This invention relates to digital loop transmission systems, and, in particular, to a means for managing a plurality of remote terminals which are networked in said systems.
Digital loop transmission systems, such as Subscriber Loop Carrier (SLC.RTM.) Systems, involve transmission of digital information between a central office and a number of remote terminals, and between the remote terminals and subscribers. Each remote terminal site includes a Site Interface Unit (SIU) which provides a data link between the central office and remote terminal, and each remote terminal includes a Bank Controller Unit (BCU) for controlling the various circuits of the terminal.
Future systems will include advanced capabilities such as inventory control of channel units, downloading of software from the central office, and special monitoring of remote terminal functions. Many of these new features will require fairly complex and expensive circuitry in the SIU to provide an appropriate link with the central office. It is, therefore, desirable to combine a plurality of remote terminals in a local area network so that the number of links to the central office is reduced. One problem with such an approach, however, is that bandwidth and power limitations preclude standard collision detection in the network. Consequently, some other means is needed to identify each remote terminal and thereby manage communication among the various remote terminals.
In other types of communications systems, it has been proposed that each module can derive a number from the first four bits of its serial number and use that number as a count to determine when to request an address from the primary station. The primary station will then assign an address to the module. The module and primary station will also transmit the module serial number for purposes of verification (see U.S. Pat. No. 4,638,313 issued to Sherwood, Jr., et al).
It is an object of the invention to provide a means for managing a network of terminals including assigning addresses thereto.